It has been customary in the design of vacuum-type circuit interrupters, to provide a vapor or a condensing shield to prevent the outward dissemination of the metallic particles during arcing, and their concomitant deposit on the inner walls of the outer insulating casing, which may be of glass or ceramic material, for example. Consequently, practically all vacuum-type circuit interrupters have such condensing shields.
Some of the shields may be disposed at the potential of one of the separable contacts, as in U.S. Pat. Nos. 2,975,256, Lee et al, or 3,244,842, Kameyama et al. Other condensing shields may, for example, be at a floating potential, such as set forth in U.S. Pat. No. 3,592,987, Lempert et al.